While Wittmann may have been known to certain elements in Allied intelligence, as Andreas points out, he was an unknown quantity to the Allied troops he was facing. I have read the First Canadian Army intelligence summaries for the Normandy campaign, and his name does not appear in any of them. Ditto for Ultra, and if his name had appeared in this product, without another source, it could not have been disseminated in any case.
Let's face it. He was an acting battalion commander and, as such, was of little import in the big scheme of things. It fell to a later generation to elevate him to near mythical status. Still, he was a good soldier who met a soldier's fate.